The effects of HIV on fertility by infection duration: evidence from African population cohorts before antiretroviral treatment availability

Abstract

OBJECTIVES: To estimate the relationship between HIV natural history and fertility by duration of infection in East and Southern Africa before the availability of antiretroviral therapy, and assess potential biases in estimates of age-specific sub-fertility when using retrospective birth histories in cross-sectional studies. DESIGN: Pooled analysis of prospective population-based HIV cohort studies in Masaka (Uganda) Kisesa (Tanzania), and Manicaland (Zimbabwe). METHODS: Women aged 15-49 who had ever tested for HIV were included. Analyses were censored at antiretroviral treatment roll out. Fertility rate ratios were calculated to see the relationship of duration of HIV infection on fertility, adjusting for background characteristics. Survivorship and misclassification biases on age-specific subfertility estimates from cross-sectional surveys were estimated by reclassifying person time from the cohort data to simulate cross-sectional surveys and comparing fertility rate ratios to true cohort results. RESULTS: HIV negative and positive women contributed 15,440 births and 86320 person years; and 1,236 births and 11240 thousand person years respectively to the final dataset. Adjusting for age, study site and calendar year, each additional year since HIV sero conversion was associated with a 0.02 (95%CI 0.01-0.03) relative decrease infertility for HIV-positive women. Survivorship and misclassification biases in simulated retrospective birth histories resulted in modest underestimates of sub-fertility by 2-5% for age groups 20-39y. CONCLUSION: Longer duration of infection is associated with greater relative fertility reduction for HIV-positive women. This should be considered when creating estimates for HIV prevalence among pregnant women and PMTCT need over the course of the HIV epidemic and ART scale-up.